Vessel repair

ABSTRACT

The invention relates to the repair of vessels, particularly refractory-lined vessels such as are used in steelmaking. Frequently there is wear on the lining of such vessels sufficient to prevent the use of the vessel without repair but insufficient to justify the costs of completely re-lining the vessel. The object of the present invention is to provide relatively simple and efficient repair apparatus (1) for applying particulate refractory material to a vessel (2) wall where required, which objective is met by apparatus to enable the repair of the refractory lining comprising a rotatable member (4), rotatably mounted substantially at the end of a carrier (3) adapted to locate the rotatable member (4) at a required position in the vessel, a drive structure (6) for the rotatable member, structure associated with the carrier to direct and deposit a particulate refractory material onto the rotatable member (4), said carrier and/or said structure associated with said carrier being circumferentially adjustable to deposit the particulate material at a predetermined position on the rotatable member and whereby to achieve a required direction of discharge of material ejected form the rotatable member.

This invention relates to the repair of vessels, and particularlyrefractory-lined vessels.

With refractory-lined vessels such as are used in steelmaking, such asfor example, furnaces, ladles, tundishes, and the like, it is inevitablethat there is wear of the refractory lining. Frequently, the wear on thelining is insufficient to justify the costs of complete relining of thevessel, but is greater than is permitted to allow the vessel to bere-used without repair.

With such as, for example, an electric arc furnace, there are knownlocations on the lining where greatest wear takes place, on the wall ofthe lining in closest proximity to each of the three electrodesordinarily employed, and circumferentially of the lining at the slagline. Similar considerations can apply to other vessels, such as basicoxygen furnaces where there are two principal points of wear of itslining at diametrically opposite locations on the line of the axisthrough the trunnions.

Conventionally, localised repair is effected by so-called gunningtechniques, where a slurry of a required refractory material is directedat the wall through a nozzle at the end of a supply hose. In somecircumstances the nozzle is hand-held requiring the operative toposition himself above the furnace with its roof removed, both hazardousand inefficient because of inconvenient positioning of an operativerelative to the required area where repair is required. In othercircumstances a nozzle is provided on a carrier to locate the nozzlewithin the furnace, with a means to enable the nozzle to be drivenarcuately. Whilst avoiding operator difficulties effective equipment isexpensive, and relatively inefficient, with noticeable constraints onthe volume/weight of refractory material that can be dispensed in unittime.

There are other known forms of equipment involving a spinning disc belowa dispensing hopper, to be lowered into the furnace, with a series ofmovable gates associated with the spinning disc attempting to controlthe direction in which material deposited on the disc will be dischargedagainst the furnace wall. Given the nature of refractory repairmaterial, equipment of this nature is prone to becoming blocked, withjamming of the gates open or closed, and with the frequent need for itto be stripped and cleaned. It is also the case that the gates cannot bea sliding sealing fit on the rotating member, allowing refractorymaterial to pass below a closed gate and simply fall to the floor, awasteful loss of refractory material. In addition, the placement of ahopper and its associated rotatable disc within a vessel must be by anoverhead crane. Overhead cranes in steelmaking plants are in constantuse, and there is a considerable inconvenience in having the overheadcrane out of commission whilst it is holding the hopper in the vesselfor the time required for repair of the lining to be completed.

With vessels such as, for example, steelmaking furnaces, it istraditionally so that a bank of loose course granular refractorymaterial is deposited as a bank at the junction of the furnace sidewalls and furnace floor to provide a smooth transition from the furnacewall to the furnace floor. During steelmaking there is inevitableerosion of the bank, frequently requiring its repair or renewal beforethe furnace can be re-used. Accurate deposit of fresh granular materialto a bank at its points of required repair has similar and comparabledifficulties with those mentioned above in connection with liningrepair.

The object of the present invention is to provide for the repair ofrefractory lined vessels free from those disadvantages mentioned above.

According to the present invention, means to enable the repair of arefractory lining of a metallurgical vessel comprises a rotatablemember, rotatably mounted at or towards the end of a carrier meansadapted to locate the rotatable member at a required position in thevessel, a drive means for the rotatable member, means operable toactivate the carrier to direct and deposit a particulate refractorymaterial on to the rotatable member said carrier and/or said meansassociated with said carrier being circumferentially adjustable todeposit the particulate material at a predetermined position on therotatable member and whereby to achieve a required direction of throw ofmaterial ejected from the rotatable member. Preferably, the rotatablemember is provided with vanes or blades.

It has been found that particulate refractory material, in wet or drycondition, deposited on to a rotatable member, is thrown from the memberin fixed angular relationship to the point of deposit of the material onto the member. Thus, by arranging for circumferential adjustability of acarrier for a rotating member, and/or a means associated with thecarrier to deposit material onto the member, material can be caused tobe thrown from the member in any required direction. In addition to thematerial being thrown from the rotating member in a required direction,it is equally the case that the material is thrown with an angularspread both transversely and vertically. Consequently, a fan-like lineardistribution of particulate material is immediately formed at therequired position on the wall of the vessel at its required position,the length of the applied material being more than adequate to extendacross the worn area at that point on the vessel wall.

With such vessels as electric arc furnaces, the wear that occurs on thewall behind an electrode is deeper immediately behind the electrode andbecomes shallower in both directions in the transverse direction. Ofnotable importance with the invention is that the manner by whichmaterial is thrown from the rotatable member is such as to create afan-like linear distribution of particulate material that is thinner atthe transverse peripheries and thicker at the centre of the fan-likelinear distribution of particulate material. When applied to the wearbehind an electrode, the result is the restructuring of the wall at thatpoint with a substantially planar surface.

It is preferred that the particulate material is deposited on therotatable member at between 80° and 120° from the approximate centreplane of the fan-like linear distribution of particulate material in thedirection opposite to that of rotation of the rotatable member. Furtherpreferably, particulate material is deposited at 100° from theapproximate centre plane of the fan-like linear distribution ofparticulate material.

The rotatable member may be a disc, a barrel, or a drum.

Thus with the rotatable member set at a position commensurate with oneextremity of a worn area on a vessel wall, rotation of the rotatablemember and the deposit of particulate material on to it causes thecreation of a repair patch by the fan-like linear distribution ofparticulate material at that point. With then the rotatable membergradually moved over the worn area the position of the patch beingformed on the wall is moved, and the whole of the worn area can berepaired with considerable ease and efficiency. Another, and mostimportant advantage, is that repair when effected in this manner and bythe invention, has the beneficial effect of the substantial, if nottotal, elimination of any problem caused by the rebounding ofparticulate material from the vessel wall, and the prevention of reboundhas the important advantage of avoiding loose particulate materialgathering on the vessel floor.

The carrier for the rotatable member may be a relatively simple roboticarm able to be brought within the vessel, and adjustable as to itsposition to locate a rotatable member mounted on the end of the roboticarm at a required start point within the vessel. The means associatedwith the carrier may be a relatively simple feed pipe to transportrefractory material to the rotatable member. Circumferentialadjustability can be provided for by having the e.g. feed pipe, securedto the e.g. robotic arm, and the robotic arm rotatable about its ownaxis. Equally, circumferential adjustability can be achieved by mountingthe e.g. feed pipe, on the e.g. robotic arm, such that at least theoutlet from the feed pipe can be rotated around the arm.

The carrier, e.g. robotic arm, may be provided with mounting means fordirect attachment to the outer wall of the vessel, with an appropriatedrive means to enable the robotic arm to be brought from an inoperativeposition outside the vessel to an operative position within the vessel.Preferably, however, mounting means for the carrier is a superstructurepositioned adjacent the vessel wall. Equally, the carrier, e.g. roboticarm, could be mounted on a tractor means to enable the carrier, e.g.robotic arm, to be brought to the side of a vessel as and when required,and the carrier e.g. robotic arm, positioned within it.

Following the emptying of a vessel, visual inspection can readilydetermine if and where repair of its wall lining is required, and if anarc furnace, if and where there has been damage/erosion of the bank thatrequires repair. The carrier can then be brought within the vessel underthe control of an operative, set as to its position, and either thecarrier rotated, or the means associated with the carrier rotated toposition the deposit point of material to the rotatable member such thatmaterial with entrained water will be thrown from the rotatable memberat the vessel wall, or dry material at the bank, precisely where repairis to be effected. To assist in the accurate deposit of dry materialthrown from the rotatable member at a bank, a deflector means can beprovided to impose a downward direction to the material as it is thrownin the required radial direction.

A further advantageous feature of the invention, in addition toproviding directional control over material ejected from the rotatablemember, is that all-round, or circumferential, application of materialcan be achieved, either by continuously rotating the carrier about itsown axis, or continuously rotating at least the feed pipe outlet aboutthe carrier whilst material is being deposited on the rotatable member.

The invention lends itself admirably to the particular circumstancesthat apply to electric arc furnaces. Ordinarily, such furnaces havethree electrodes, and it is well-known in the art that such furnaceshave known principal wear points, such as on the wall behind each of theelectrodes and circumferentially at the slag line. Thus, equipment inaccordance with the invention may be provided with a control means suchthat on first introduction of the carrier/robotic arm into the furnace,the arm, or the feed pipe outlet for refractory material, is set at aposition where material will be thrown from the rotatable member towardsone worn point on the lining, with the arm or the supply hose outletindexable to bring it to a predetermined second, and subsequently to apredetermined third, position, and whereby the repair of the three knownwear points can be effected in an automatic, or semi-automatic, manner.Following the repair of such wear points on the wall, the arm can beadjusted to put the rotatable member on the slag line, and the arm orthe supply hose outlet continuously rotated to effect circumferentialapplication of material to repair the wear at the slag line.

Similar considerations apply to basic oxygen furnaces, where, if on avisual inspection it is confirmed that unacceptable wear has taken placeat diametrically opposite points on the wall lining or other wear areas,such as the charge pad and nose cone, the control means can be set suchthat the equipment is brought to a condition where material is thrown atone worn point, and the carrier or the supply hose outlet indexed tocause material to be thrown at the second worn point on the lining.

With other vessels, such as, for example, ladles and tundishes, there isa more general wear of the linings. Here the control equipment can beemployed to provide a continuous adjustment of the position of therotatable member, in conjunction with a rotation of the carrier or thesupply hose outlet, to achieve the automatic provision of a coating ofrefractory material over the full circumference of the lining and overany required distance.

The invention will now be described, in greater detail, by way ofexample only, with reference to the accompanying drawings, in which:

FIG. 1 is a sectional side elevation through the lower end of a carriermeans, associated rotatable member and material deposit means;

FIG. 2 is a section on the line II--II of FIG. 1; and

FIG. 3 is a schematic representation illustrating the manner by whichmaterial is thrown from the rotatable member.

In the drawings, a means 1 to enable the repair of a refractory liningof a metallurgical vessel 2 is formed by a carrier means 3 in the formof a mast that may be part of a robotic arm that can be positionedwithin the metallurgical vessel as and when required. At the end of thecarrier means 3 a rotatable member in the form of a spinner disc 4 isprovided having a drive shaft 5 extending to a hydraulic motor 6 locatedwithin the adjacent end of the carrier means 3. In fixed spacedrelationship to the spinner disc 4 is a location plate 7 for a materialfeed pipe 8 extending along the length of the carrier means 3. Thelocation plate 7 is secured to a housing 9 itself attached to the end ofthe carrier means, the housing 9 serving as a bearing housing for taperroll bearings 10 for the drive shaft 5.

In one form of construction, the material feed pipe 8 is directlyattached to the carrier means 3, and the carrier means 3 together withthe feed pipe 8 being mounted for rotation about the longitudinal axisof the carrier means, to adjust the position of the feed pipe 8 aboutthe longitudinal axis of the carrier means 3 and hence the axis ofrotation of the spinner disc 4. In an alternate form of construction,the material feed pipe 8 and the location plate 7 can be rotated aboutthe carrier means 3, to achieve the same result, the positioning of thefeed pipe about the longitudinal axis of the carrier means and hence theaxis of rotation of the spinner disc.

As is shown, it is highly desirable that the spinner disc is providedwith vanes 11 generally radially disposed and of shallow, convex shapein the direction of rotation of the spinner disc.

The invention is based on the surprising realisation that with, such as,a spinner disc rotating, particulate refractory material, in wet or drycondition, can be applied against it at a predetermined point, and whichwill be ejected from the spinner disc as a fan-like linear distribution,as is illustrated schematically in FIG. 3, with a substantiallyguaranteed mean angular relationship of approximately 100° between thepoint of deposit and the direction of throw of the material, and whichrenders totally superfluous the need for any containing walls or movablegates surrounding the spinner disc, with the total avoidance of any riskof the clogging of particulate refractory material and consequentialneed for the provision of a drive motor of higher power than is requiredto rotate the spinner disc because of the absence of any frictionalforces that need to be overcome.

The invention lends itself ideally to both manual and automatic control.Thus, a furnace or other metallurgical vessel can be visually inspectedby an operative to determine the position of any worn areas on thelining of the vessel, and following which the carrier means 3 can bebrought within the furnace to position the spinner disc 4 at one edge ofa worn area and to position the feed pipe 8 in relation to the spinnerdisc 4 such that material urged into contact with the spinner disc willbe ejected from the spinner disc in the required direction to apply thefan-like linear distribution of particulate refractory material to theworn area, and the carrier means 3, along with the spinner disc 4,adjusted in position to cause the fan-like linear distribution toprogress along the worn area. Thus, once one worn area has been attendedto, the operative can bring the carrier means 3 and hence the spinnerdisc 4 to a required different position with appropriate adjustment ofthe position of the feed pipe 8 to enable the fan-like lineardistribution of particulate material to be applied against a second orsubsequent worn area.

With certain metallurgical vessels, such as, for example, electric arcfurnaces, it is well-known that there will be principal wear points onthe vessel lining such as, for example, behind each of the electrodesand circumferentially at the slag line, and in such as, basic oxygenfurnaces, at diametrically opposite points on the wall lining and at,such as, the charge pad and nose cone. Thus, microprocessor controlmeans may be provided and preprogrammed such that with the carrier means3 brought within a particular furnace to position the spinner disc at arequired height, and with the feed pipe adjusted such that particulatematerial will first be thrown against one worn point, the microprocessorcontrol can readily cause the movement of the carrier and hence thespinner disc to cause the application of particulate refractory materialover the area of the first worn point, following which themicroprocessor can bring the carrier and re-position the feed pipe 8 toenable the particulate refractory material to be thrown against asecond, or subsequent, worn point around the inner periphery of thevessel lining.

I claim:
 1. A means to enable the repair of a refractory lining of ametallurgical vessel comprising a rotatable member, rotatably mountedsubstantially at the end of a carrier means adapted to locate therotatable member at a required position in the vessel, a drive means forthe rotatable member, a means operable to activate the carrier means todirect and deposit a particulate refractory material onto the rotatablemember, said carrier means and/or said activation means with saidcarrier means being circumferentially adjustable to deposit theparticulate material at a predetermined position on the rotatable memberand whereby to achieve a required direction of discharge of materialejected from the rotatable member.
 2. The repair means of claim 1,wherein the rotatable member is provided with vanes or blades.
 3. Therepair means of claim 1 or claim 2, wherein the particulate material isdeposited on the rotatable member at between 80° and 120° from the meandirection of discharge of the particulate material from the rotatablemember.
 4. The repair means of claim 3, wherein the particulate materialis deposited on the rotatable member at approximately 100° from the meandirection of discharge of the particulate material from the rotatablemember.
 5. The repair means of claim 1 wherein the feed pipe means ismade circumferentially adjustable by securing said feed pipe means tosaid carrier means, and the carrier means is positioned and arrangedrotatable relative to the rotatable means, whereby rotation of thecarrier means causes rotation of the feed pipe means.
 6. The repairmeans of claim 1 wherein the feed pipe means is made circumferentiallyadjustable by securing said feed pipe means directly to said carriermeans so that the feed pipe means can be rotated around the carriermeans.
 7. The repair means of claim 1 wherein the carrier means is arobotic arm able to be brought within the vessel and adjustable tolocate the rotatable member mounted at the end of the robotic arm at arequired start point within the vessel.
 8. The repair means of claim 7,wherein the robotic arm is provided with a mounting means for directattachment to the outer wall of the vessel with a drive means to enablethe robotic arm to be brought from an inoperative position outside thevessel to an operative position within the vessel.
 9. The repair meansof claim 7, wherein the carrier means is provided with a mounting meansthat is a support structure positioned adjacent the vessel wall.
 10. Therepair means of claim 7, wherein the carrier means is mounted on atractor means to enable the carrier means to be brought to the side of avessel when required and to position the carrier means within thevessel.
 11. The repair means of claim 1 wherein a manual adjustmentmeans are provided for the positioning of the carrier means within avessel and the positioning of the activation means to deposit aparticulate refractory material onto the rotatable member.
 12. Therepair means of claim 1 wherein an automatic microprocessor means areprovided for the positioning of the carrier means within a vessel andthe positioning of the activation means to deposit a particulaterefractory material onto the rotatable member.